Hackaday Links: June 29, 2014

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Ever see a really cool build on YouTube with no build details at all? Frustrating, right? That’s us with the NES Keytar covering the Game of Thrones theme. He’s using a Raspi with the sound chip in the NES to do live chiptunes. Freakin’ awesome. There’s also the ST:TNG theme as well.

A few years ago the folks at Oculus had an idea – because of cellphones, small, high resolution displays are really cheap, so why not make VR goggles? At Google IO this week someone figured out everyone already has a cellphone, so just wrap it in some cardboard and call it a set of VR goggles. You can get a kit here, but the only difficult to source components are the lenses.

What happens when you put liquid nitrogen under a vacuum? Well, it should evaporate more, get colder, and freeze. Then it breaks up into solid nitrogen snow. No idea what you would do with this, but there ‘ya go. Oh, [NC], we’re going to need a writeup of that LN2 generator.

About a month ago, the House4Hack hackerspace in South Africa told us of their plans to bring a glider down from 20km above the Earth. They finally launched it, The CAA only allowed them to glide back from 6km (20,000 feet), but even from there the foam glider hit 230kph (124 knots). That’s a little impressive for a foam FPV platform, and we’re betting something with a larger wingspan would probably break a spar or something. Shout out to HABEX.

All the electronic dice projects we’ve seen have one thing in common: they’re not cubes. Thus uberdice. It’s six nine-pixel displays on the faces of a cube, powered by a battery, and controlled by an accelerometer. Yes, it is by far the most complicated die ever made, but it does look cool.

High Altitude Glider Will Be Dropped From A Balloon!

[House4Hack] and [HABEX] have teamed up to design and build a glider system that can be taken up 30-40km via a weather balloon, dropped, and flown home via FPV.

Of course, this has been done before, but you know what, it’s such a cool experiment, and so few people have done it… who cares! The goal is to hit at least 20km altitude, hope for 30km, and if possible — 40km would break records. For reference, the one we linked made it 33km up.

The plane is a Mini-talon V-tail, which was donated to them by their local hobby shop as a sponsorship. It features an ArduPlane Autopilot module, a 1.2GHz video transmitter, a long range 433MHz receiver for the control signal, and a telemetry data link at 433MHz connected to the ArduPlane. Two GoPro cameras make up its eyes, and it also has a custom release mechanism for letting go of the weather balloon.

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Reach Out And Touch Your Next Project With Long Range RC Controller

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Long range wireless control of a project is always a challenge. [Mike] and his team were looking to extend the range of their current RC setup for a UAV project, and decided on a pair of Arduino mini’s and somewhat expensive Digi Xtend 900Mhz modems to do the trick. With a range of 40 miles, the 1 watt transceivers provide fantastic range. And paired with the all too familiar Arduino, you’ve got yourself an easy long range link.

[Mike] set the transmitter up so it can plug directly into any RC controller training port, decoding the incoming signal and converting it into a serial data package for transmitting. While they don’t provide the range of other RF transmitters we’ve seen, the 40 mile range of the modem’s are more than enough for most projects, including High Altitude Balloon missions.

The code for the Arduino transmitter and receiver sides is available at their github. Though there is no built-in error correction in the code, they have not had any issues.  Unfortunately, a schematic was not provided, but you should be able to get enough information from the images and datasheets to construct a working link.

 

Nearspace Environmental Chamber

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If you’re going to send some hardware up to 100,000 feet, where atmospheric pressure is 1% of what we enjoy on the surface and temperatures swing down to where Fahrenheit and Celsius don’t matter anymore, you might want to do a bit of testing to make sure everything works before launch. With a few bits of PVC, though, that’s a piece of cake.

There were several environmental conditions to take into consideration; the near vacuum experienced by high altitude balloons would be replicated by a refrigerator compressor, the increased solar flux is simulated by a light bulb, and the cold temperatures provided by a chunk of dry ice.

For a proper high altitude, low temperature environmental chamber the test payload should be cooled down via radiation with tubes filled with liquid nitrogen embedded in the walls. This is the NASA way of doing things, but for the budget of $200, [arko]’s chamber simulates a high altitude environment just fine.

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Launching A Balloon And Not Landing In The Ocean

In just a few short hours, the Yale Undergraduate Aerospace Association will launch their 4th high altitude balloon project into the rarefied air of the stratosphere and with any luck bring back pictures of the view high above Connecticut  Long Island, Rhode Island, and Martha’s Vineyard.

Inside their surprisingly strong unibody chassis is two GoPro cameras and a triple-redundant telemetry system consisting of a custom radio system capable of transmitting over 40 miles, a cell-phone based comms system and a SPOT satellite tracker.

There is one very large problem the Yale Aerospace team has had to cope with; Because they’re launching their Skyview balloon from the eastern seaboard of the US, it’s very likely their payload could end up taking a drink in the Atlantic. To solve this problem, the team developed a novel cut-down solution: a piece of nichrome heater wire is wrapped around the line tying the payload to the balloon. If the hardware receives a signal from the ground, or has a software problem, or runs out of battery power, the nichrome circuit will release the balloon from its launch vehicle to hopefully return it to solid ground.

The Yale Aerospace team has also written a custom iOS app allowing the chase cars to track the balloon in real time – a great feature if you’re trying to communicate with several cars going down the highway. You can check out the live data from the balloon on the Yale Aerospace tracking site or just head over to their twitter to read the latest news about the flight.

Checking Out Mount Olympus From 38 Km

The image above shows Mount Olympus in the center, with a tiny bit of the western suburbs of Thessaloniki, the second largest city in Greece, in the lower right hand corner. These two points are 70 kilometers apart, but we’re not seeing a picture taken from the International Space Station. This is a picture from the SlaRos project, a high altitude balloon launched last summer that ascended to 38 kilometers above Greece.

On SlaRos’ project page (Facebook warning), the team covers the hardware that went in to lofting a camera high above the cruising altitude of commercial airplanes. A GPS module tracked the balloon in real time and relayed this to a GSM module to the mobile command and tracking team.

There are a ton of high altitude pictures of Greece over on the project’s Facebook page as well as a time lapse video of the Grecian wilderness after the SlaRos payload landed. The payload spent a full night in a field before it was recovered, but we’re very glad the team was able to recover these awesome pictures.

Sending A Raspberry Pi To 130,000 Feet

We knew this wouldn’t take long. [David] sent a high altitude balloon into the upper atmosphere last weekend using a Raspberry Pi as the brains of the payload.

[David]’s payload consisted of a Raspberry Pi, natch, with a Logitech webcam, GPS receiver, and six AA batteries wired into a LDO regulator with a monstrous heat sink to keep everything in the EPX foam enclosure relatively warm in the frigid rarefied air of near space.

A high altitude balloon isn’t much fun without some real-time data coming down from the upper atmosphere, so [David] used a Radiometrix NTX2 transmitter module (anyone know of an equivalent part for the USA?) that transmits a measly 10 milliwatts. Even though the transmitter has an ‘official’ range of 500 meters, [David] got word of image data being received in Northern Ireland, over 500 km away.

We’re pretty impressed with [David]’s flight  – and the fact that his flight is now 12th place on the list of UK balloon altitude records – but now we’re wondering what could be done with another Raspi flight to near space. [David] had a lot of computing horsepower up there, enough to get images from a webcam and send them down to earth. Now we’re wondering what else could be done with a Raspberry Pi in space.

You can check out the GoPro video of the very fast decent after the break, or check out the received images on [David]’s Flickr.

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